1. Field of the Invention
The present invention generally relates to a work-sheet folding apparatus which includes a work-sheet support plate on which a work sheet is placed, and which folds an outer peripheral portion of the work sheet, and particularly to a work-sheet folding apparatus for a pocket setter which sets or forms a pocket.
2. Related Art Statement
There is known a pocket setter which folds an outer peripheral portion of a pocket-forming work sheet so as to have a shape corresponding to a pocket, and which automatically sews the thus folded work sheet to a base work sheet, such as a front body, to form the pocket in a predetermined area thereon.
For example, Japanese Utility Model Application laid open for inspection under Publication No. 3-103083 discloses a work-sheet folding system including a folding machine which folds an outer peripheral portion of a pocket-forming work sheet, and a sewing machine which sews the folded outer peripheral portion of the pocket-forming work sheet.
As shown in FIG. 3(a) to 3(d) of the above Japanese document, the pocket-forming work sheet P includes a hem portion 60 corresponding to an opening of a pocket. The hem portion 60 is reinforced by being folded back one or two times. The work sheet P also includes an outer peripheral portion 70. When the outer peripheral portion 70 is folded back by folding members 35, opposite end portions M of the peripheral portion 70 which correspond to opposite end portions of the hem portion 60 are additionally folded back by chamfering plates 55 to provide two "stacked" portions 80. Each of the stacked portion 80 consists of six layers or sheets in the case where the hem portion 60 is reinforced by being folded back one time, and consists of nine layers or sheets in the case where the hem portion 60 is reinforced by being folded back two times. In each case, each stacked portion 80 has a great thickness. Hence, a table 14 of the prior pocket setter has a recess 50 in a predetermined area corresponding to the hem portion 60 of the work sheet P. The recess 50 has a depth corresponding to the thickness of each stacked portion 80. Thus, the folding members 35 can be adjusted to take their positions lower by the depth of the recess than those taken by folding members of other known pocket setters. Since the folding members 35 and the chamfering plates 55 can be retracted away from the work sheet P without drawing out the stacked portions 80, the stacked portions 80 are kept intact without being deformed.
However, the depth of the recess 50 formed in the table 14 cannot be changed. Either a thick fabric such as denim or a thin fabric such as soft denim or silk may be used as the pocket sheet P and a front-body sheet to which the pocket sheet P is sewn to form a pocket thereon. In the case where the depth of the recess 50 is too great, stacked portions 80 of a thin work sheet cannot be appropriately pinched or pressed between the bottom of the recess 50 and a work-sheet support plate 24. In this case, the stacked portions 80 cannot be kept intact when the folding members 35 and the chamfering plates 55 are retracted away from the support plate 24. On the other hand, in the case where the depth of the recess 50 is too small, stacked portions 80 of a thick work sheet are pinched or pressed, with too great a pressure, between the bottom of the recess 50 and the support plate 24. In this case, when the folding members 35 and the chamfering plates 55 are retracted away from the support plate 24, the stacked portions 80 are drawn out and cannot be kept intact, either.
The recess 50 includes an inclined portion 53 on the side of the sewing machine 11. When the work sheet P whose outer peripheral portion has been folded back by the folding machine is moved to a sewing position where the sewing machine 11 is provided, the stacked portions 80 of the work sheet P is likely to be out of shape, because the stacked portions 80 must climb up the inclined portion 53 of the recess 50. Even the shape of the work sheet P corresponding to the shape of the final pocket may be deformed.